The elderly population is at increased risk of visual impairment and loss of functional independence. Little is known about either the pathophysiological causes of visual impairment, other than reduced visual acuity, or about the impact of visual impairment on functional disability. We propose to examine a representative sample of 2320 community-dwelling persons 65 to 84 years of age who reside in Salisbury, MD, to determine the association between specific components of visual loss (e.g. reduced contrast sensitivity or visual field defects) and specific types of functional disability (e.g. impaired mobility or reading). Visual impairment will be evaluated with psychophysical measures of static and dynamic visual acuity, contrast sensitivity, glare sensitivity, glare recovery, scotopic sensitivity, visual fields, and stereoacuity. Functional disability will be evaluated with standardized questionnaires and performance-based measures of reading, face recognition, mobility, and representative daily activities (ADLs and IADLs). All participants will receive a comprehensive assessment of co-morbid conditions such as arthritis and cardiovascular disease, and effect modifiers such as cognitive and psychosocial factors as part of Core Project B. We will determine how co-morbid conditions and effect modifiers alter the association of visual impairment with functional disability. Ocular disease will be assessed by photographs of the lens and macula, and by clinical examination of all participants who are visually impaired. We will determine the extent to which age-related visual changes can be attributed to pathological causes, including early changes in the lens and macula. Each participant will be evaluated twice during the course of this five-year study, separated by a 20-month interval. This will provide an opportunity to evaluate prospectively the relationship between the development of visual impairment and changes in functional status. A better understanding of the manner in which visual impairment limits performance of specific tasks can provide the basis for developing targeted interventions to maximize function in older individuals.